[llvm] [IR2Vec] Initial infrastructure for MIR2Vec (PR #161463)

[LLVM Continuous Integration via llvm-commits]

llvm-ci wrote:

LLVM Buildbot has detected a new failure on builder `clang-x64-windows-msvc` running on `windows-gcebot2` while building `llvm` at step 4 "annotate".

Full details are available at: https://lab.llvm.org/buildbot/#/builders/63/builds/11113

<details>
<summary>Here is the relevant piece of the build log for the reference</summary>

```
Step 4 (annotate) failure: 'python ../llvm-zorg/zorg/buildbot/builders/annotated/clang-windows.py ...' (failure)

```

</details>

https://github.com/llvm/llvm-project/pull/161463